The gift of free time when the intern is teaching is equaled by the amount
of paperwork required in our state - however, if you get the right one, it
is very rewarding. I once sent one "back" as ill prepared (and because I
thought the kids would probably kill her if I left her alone with them).
Some people shouldn't be teachers and this is usually really apparent
right away - be sure you have the right to ask to have the intern removed
if necessary.